• Title, Summary, Keyword: column-slab joint

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Behaviour of RC beam-column joint with varying location of construction joints in the column

  • Vanlalruata, Jonathan;Marthong, Comingstarful
    • Earthquakes and Structures
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    • v.20 no.1
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    • pp.29-38
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    • 2021
  • According to ACI 224.3R-95 (ACI, 2013), construction joints (cold joint) in the column are to be provided at the top of floor slab for column continuing to the next floor and underside of floor slab and beam. A recent study reveals that providing cold joint of the mentioned location significantly reduced the seismic performance of the frame structures. Since, the construction joints in multi-story frame structures normally provided at the top of the floor slabs and at soffit of the beam in the column. This study investigated the effect of construction joint at various location in the column of beam-column joint such as at the top of floor slab, soffit level of the beam, half the depth of beam below the soffit of the beam and at a full depth of the beam below the soffit of the beam. The study revealed that there is an improvement in seismic capacity of the specimens as the location of cold joint is placed away from the soffit of the beam for lower story column.

Ductility of Column-Slab eoint in R/C Flat Plate System (플랫 플레이트 구조의 기둥.슬래브 접합부 연성에 관한 연구)

  • 김형기;박복만
    • Journal of the Korea Concrete Institute
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    • v.12 no.4
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    • pp.113-119
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    • 2000
  • The R/C flat plate system provides architectural flexibility, clear space, reduced building height, simple formwork, which consequently enhance constructibility. One of the serious problems in the flat plate system is brittle punching shear failure due to transfer of shear force and unbalanced moments in column-slab joint. Recently, the flat plate system accompanied with shear walls to resist the lateral loads is applied to high-rise buidings. Although the flat plate system is not considered in design as part of the lateral load-resisting system, it is required that this system keeps the ductile behavior for the lateral displacement of the building. However, it is unclear whether the column-slab joint possesses ductility enough to survive the lateral deformation. The objective of this paper is to investigate the major parameters that influence the ductility of R/C flat plate system by examining the existing experiments on column-slab joint. The effects of gravity load and shear reinforcement on the ductility of the flat plate system are presented.

Transverse Concinement and Slab Effect on Shear Behavior of Beam-Column Connection (보-기둥 접합부의 전단거동에 대한 슬래브 및 횡구속 영향)

  • 장극관;서대원;방세용
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.419-422
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    • 1999
  • This study was intended to investigate the cyclic behavior of high strength concrete beam-column connection. Four assemblies were designed 2/3 scale beam-column-slab joint and tested. The obtained results are follows. 1) The transverse beams increase the shear resistance and ductility of joint, 2) The slab was contributed to increase of the flexural capacity of the beam, but was not contributed to increase the joint ductility under lateral loads.

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Benefits of Puddling of Fiber Reinforced UHSC for Enhanced Transmission of Column Loads

  • Lee, Joo-Ha;Kim, Gyu-Dong;Yoon, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.75-78
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    • 2005
  • This study reports on the structural characteristics of slab-column connections using an ultra-high-strength-fiber-reinforced concrete. Compression tests were performed on two slab-column and four isolated column specimens. During the column load tests were performing on the slab-column specimens, the slab loads were also applied to consider actual confinement condition at the slab-column joint. The main parameter investigated was the ' puddling ' of ultra-high-strength-fiber-reinforced concrete. This paper also investigates the effects of some parameters on slab-column specimens and isolated column specimens without the surrounding slab for their ability to transmit axial loads from the ultra-high-strength concrete columns through slab-column connections. The beneficial effects of the ultra-high-strength-fiber-reinforced concrete puddling on the transmission of column loads through slab-column connections are demonstrated.

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Improved Transmission of UHSC Column Loads by Puddling of Fiber Reinforced UHSC (강섬유 보강 초고강도 콘크리트의 확대 타설을 통한 기둥 하중 전달 성능 향상)

  • Lee, Joo-Ha;Yang, Jun-Mo;Lee, Seung-Hoon;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.19 no.2
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    • pp.209-216
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    • 2007
  • This study reports on the structural characteristics of slab-column connections using fiber-reinforced ultra-high-strength concrete (UHSC). Compression tests were performed on two slab-column and four isolated column specimens. In the column load tests, slab loads were also applied on the slab-column specimens so that the actual confinement condition at the slab-column joint was considered. The main parameter investigated was the "puddling" of fiber-reinforced UHSC. This paper also investigates the effects of some parameters, such as confinement of slab concrete, steel fibers, and concrete strength of the joint, related to the ability of the slab-column specimens and isolated column specimens without the surrounding slab to transmit axial loads from the UHSC columns through slab-column connections. Furthermore, the ACI Code (2005) and the CSA Standard (2004) are compared to the experimental results. The beneficial effects of the puddling of fiber-reinforced UHSC on the transmission of column loads through slab-column connections are demonstrated.

Experimental Study of High Strength Concrete Beam-Column-Slab Connections subjected to cyclic loading (고강도 콘크리트 보-기둥-슬래브 접합부의 반복하중 실험)

  • 오영훈;오정근;장극관;김윤일
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.339-344
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    • 1995
  • In the design of ductile moment-resisting frames (DMRFs) following the strong column-weak beam dsign philosophy, it is desirable that the joint and column remain essentially elastic in order to insure proper energy dissipation and lateral stability of the structure. The joint has been identified as the "weak link" in DMRFs because any stiffness or strength deterioration in this region can lead to substantial drifts and the possibility of collapse due to P-delta effects. Moreover, the engineer is faced with the difficult task of detailing an element whose size is determined by the framing members, but which must resist a set of loads very different from those used in the design of the beams and columns. Four 2/3-scale beam-column-slab joint assemblies were designed according to existing code requirements of ACI 318-89, representing interior joints of DMRFs with reinforced high strength concrete. The influence on aseismic behavior of beam-column joints due to monolithic slab, has been investigated.estigated.

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Hysteretic Behavior of Slab-Column Joint Using Bended Type Shear Reinforcement (절곡형 전단보강근을 사용한 슬래브-기둥 접합부의 이력 거동)

  • Lee, Hyun-Ho;Lee, Do-Bum;Lee, Li-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.3
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    • pp.211-218
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    • 2006
  • From the development of residential flat plate system, continuously bended shear reinforcement is developed for the prevention of punching shear. To know the punching shear capacity of developed shear reinforcement in slab-column joint, structural test is performed. The testing parameters are shear reinforcement types, such as no reinforcement, bended shear reinforcement, and head stud reinforcement. To verify the lateral capacity, cyclic load is applied under the constant vertical load condition. The results of tests are compared to as global displacement, slab-column joint strength. From the test results, the resisting capacity of developed shear reinforcement system has a good performance in the story drift ratio.

Cyclic behaviour of concrete encased steel (CES) column-steel beam joints with concrete slabs

  • Chu, Liusheng;Li, Danda;Ma, Xing;Zhao, Jun
    • Steel and Composite Structures
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    • v.29 no.6
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    • pp.735-748
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    • 2018
  • In this paper, the cyclic behavior of steel beam-concrete encased steel (CES) column joints was investigated experimentally and numerically. Three frame middle joint samples with varying concrete slab widths were constructed. Anti-symmetrical low-frequency cyclic load was applied at two beam ends to simulate the earthquake action. The failure modes, hysteretic behavior, ultimate load, stiffness degradation, load carrying capacity degradation, displacement ductility and strain response were investigated in details. The three composite joints exhibited excellent seismic performance in experimental tests, showing high load-carrying capacity, good ductility and superior energy dissipation ability. All three joint samples reached their ultimate loads due to shear failure. Numerical results from ABAQUS modelling agreed well with the test results. Finally, the effect of the concrete slab on ultimate load was analyzed through a parametric study on concrete strength, slab thickness, as well as slab width. Numerical simulation showed that slab width and thickness played an important role in the load-carrying capacity of such joints. As a comparison, the influence of concrete grade was not significant.

Seismic behavior and strength of L-shaped steel reinforced concrete column-concrete beam planar and spatial joints

  • Chen, Zongping;Xu, Deyi;Xu, Jinjun;Wang, Ni
    • Steel and Composite Structures
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    • v.39 no.3
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    • pp.337-352
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    • 2021
  • The study presented experimental and numerical investigation on the seismic performance of steel reinforced concrete (SRC) L-shaped column- reinforced concrete (RC) beam joints. Various parameters described as steel configuration form, axial compressive ratio, loading angle, and the existence of slab were examined through 4 planar joints and 7 spatial joints. The characteristics of the load-displacement response included the bearing capacity, ductility, story drift ratio, energy-dissipating capacity, and stiffness degradation were analyzed. The results showed that shear failure and flexural failure in the beam tip were observed for planar joints and spatial joint, respectively. And RC joint with slab failed with the plastic hinge in the slab and bottom of the beam. The results indicated that hysteretic curves of spatial joints with solid-web steel were plumper than those with hollow-web specimens. The capacity of planar joints was higher than that of space joints, while the opposite was true for energy-dissipation capacity and ductility. The high compression ratio contributed to the increase in capacity and initial stiffness of the joint. The elastic and elastic-plastic story deformation capacity of L-shaped column frame joints satisfied the code requirement. A design formula of joint shear resistance based on the superposition theory and equilibrium plasticity truss model was proposed for engineering application.

Nonlinear Finite Element Analysis on the Transmission of Column Loads through Slab-Column Connections

  • Lee, Joo-Ha;Yoon, Young-Soo;Sohn, Yu-Shin;Lee, Seung-Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.466-469
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    • 2006
  • This paper presents the structural characteristics of slab-column connections by using nonlinear finite element analysis. FEA considering material non-linearity was performed to investigate average column strain, failure mode, principal stress distribution, and steel yielding conditions for various slab-column members. In addition, to investigate alternative methods for improving the strength of interior column-slab joints, some specimens were provided with different reinforcing types of high-strength concrete puddling, high-strength column longitudinal steels, dowel bars, and high-strength concrete core. To make certain of the reliability of the analytical program, analysis results for concrete material model developed and two specimens with and without puddling were compared with experimental results. It was found that providing the alternative reinforcing methods in the slab-column joint results in a significant improvement in performance. This includes an increase in the axial compressive strength, greater loading stiffness, and ductility.

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